


A new Life

by KillerOfHope



Category: Supernatural
Genre: Age Difference, Alpha Sam, Alpha/Beta/Omega Dynamics, Anal Play, Butt Plugs, Community: spnkink_meme, De-Aged Dean Winchester, Episode: s10e12 About A Boy, M/M, Omega Dean, References to Knotting, Top Sam
Language: English
Status: Completed
Published: 2016-09-03
Updated: 2016-09-03
Packaged: 2018-08-12 18:17:14
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 2,290
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/7944457
Author URL: https://archiveofourown.org/users/KillerOfHope/pseuds/KillerOfHope
Summary: <blockquote class="userstuff">
              <p><b>Prompt Fill for SPN Kinkmeme:</b> AU for S10E12 - "About a boy"</p>
<p>The witch wasn't just deaging adults, she had them turned into Omegas as well, since she preferred the taste of fresh young Omegas. The cake she and Hansel fed their victims was spiked with magically enhanced Alpha sperm to ensure a quick turn. So when Dean showed up at their motelroom, Sam wasn't just faced with a teen version of his brother, but with a newly presented Omega.</p>
            </blockquote>





	A new Life

**Author's Note:**

> **Author's Note:** If you wish to read the whole prompt, go [here.](http://spnkink-meme.livejournal.com/114987.html) The biggest change is that I've thrown the requested dub/non-con thing out of the window. Here it's an already established relationship with an inexperienced Dean. As far as Dean is concerned it's absolutely consensual. I also wasn't sure how old Dean is in S10E12 ... so I made him roughly 14/15 since I'm not comfortable with writing them any younger. 
> 
> Please enjoy.

Sam runs a finger downs his brother's spine and watches how Dean shivers in anticipation. Ever since the witch had turned him from an adult Alpha to a teenage omega Dean became so much more sensitive to touch. When the fingers slips into the cleft of Dean's small ass, his - now little - brother wriggles. 

"It's strange, Sammy," Dean says, muffled by the pillow. But he doesn't pull away. 

"We've done this before. I told you that you need this now," Sam explains and bites carefully into Dean's shoulder. Under him his little brother moans and presses his ass against Sam's groin, into the finger rubbing against his hole. "Or am I wrong?" 

Dean whimpers a little and buries his face into his elbow. It's shameful how he can't fight against what his body demands. He always feels hot, is always horny and ... always a little slick. 

"N-no," Dean gasps as Sam pulls Dean's thighs apart and wetness splashes forth. It runs down his skin and while it's just a drop right now, Dean knows that there will be more. "God, Sammy. Fuck me, please..." 

"Not yet, Dean," Sam says. Instead he works a finger inside his brother who is so very, very tight. It's teasing, not all the way in but for Dean and his unfamiliar it's enough. 

Drawing in a long and shaky breath Dean looks over his shoulder, needs the confirmation that there's a strong Alpha in charge of him. Before he always though Sam's huge frame to be ridiculous. Now thankful because ... fuck, no one would dare to go against Sam. Would dare to touch him as long as Sam is there. Even being pinned down by an Alpha almost twice as large as him is a relief rather than a threat. 

"You feel so big already," Dean pants as Sam pushes the finger in and out. But that might be just the hand on his hip, being so large in comparison to himself. Even the grip is strong enough to leave bruises in the morning despite the fact how careful Sam is.

"That's nothing against my cock, Dean," Sam whispers, his hot breath grazing against Dean's ear. The now younger Winchester tries to buck against the Alpha holding him down but Sam doesn't even have to use half of his weight to keep Dean from slipping away. Adding another fingers, Sam asks, "Do you feel a burn, Dean?"

It's more rhetorical because the passage around his fingers is slowly getting wetter, keeps producing slick the more Sam rubs the flesh.

"No. No, I'm good," Dean rasps in a tight voice. "Ngh, good ... it's good." 

Were Dean a partner he had chosen for the night, Sam would be less careful. But Dean is a teenager now and his responsibility. It's up to him to make sure Dean is comfortable in his new skin because it's unlikely that they'll ever find a cure. The witch wanted proper Omega child flesh, not just an Alpha looking like one. Sam is still a little puzzled how she managed it. Despite all rumors and bad porn movies it's not easy to turn someone into an Omega. Perhaps this is why she needed to combine the turning with a deaging spell. Only in the three short years between 14 and 17 it's possible to influence which course the inner biology is going to take. 

When Sam scissors his fingers to stretch Dean further a stream of wetness gushes forth and his brother - his son, if Sam is truthful - lets out a cry. 

"Don't worry, little one. I'll take care of it," Sam soothes his distress little brother and plunges his fingers deeper. 

The image of needy omega doesn't come from anywhere. Sadly it's a fact that omega experience too much arousal before they're ready to get fucked. Giving into an Omega's demands could very well mean harming them. And Sam is never going to do that to Dean. Their height difference is enough reason to be careful already. He doesn't want Dean to tear a muscle. 

"Please...," Dean begs. "Come on, please. Let me feel it. Put your cock inside me, please!" 

He has forgotten who he used to be. That he's on all fours, kneeling on a bed with Sam over him. All he wants to be mounted, to have something counter the offending feeling of too much wetness inside him. Right now it's freely running down is thighs and staining the bed. It's far more distracting than his hard cock. Sam hasn't even touched it once, is focusing only on Dean's ass and yet he doesn't mind. Dean wouldn't mind not having an orgasm as long as this ends with Sam widening him, impaling him with that large dick. 

Dean is so drenched in slick that surely Sam could just slip in. 

"Soon," Sam promises and pulls Dean up against his chest. 

His little brother gasps as Sam pulls his fingers out and immediately pushes his small ass against Sam's groin. Wriggling in his arms Sam is pleased to see that Dean's body is reacting as it should, attempting to wetting Sam's hard prick as much as he can while it's pressed against his entrance. 

"Open your mouth," Sam commands and holds the fingers wet from Dean's slick in front of his brother. 

With the boy pressed against his chest and unable to move, Dean can only keen when Sam allows him to suck at the fingers. Making a pleased sound, Dean closes his eyes and bobs his head up and down. Sam watches, aching to witness Dean doing this with a real cock but his little brother isn't ready for that yet. They need to go slow and the whole point in this is to lead the youngest member of his pack through puberty. But since Dean is sufficiently distracted, Sam pulls the cheeks of the small tight ass apart. He grinds head of his cock against the puffy entrance but Dean barely reacts.

So Sam pushes forward a little, waits if Dean's new body shows an unusual response but the hole just throbs around his dick, tries to draw the Alpha deeper by clenching around him. 

"Nngh...," Dean moans, a little delirious. He's so lost in his task that he barely notices how Sam slides deeper into him. 

Dean's reaction makes Sam protective, makes grip the small hips tight. To think what could've happened if someone else gotten their hands on Dean. Sam swears to himself that no one is ever going to touch in the next years. He'll fuck him every morning, every evening so that there's no doubt that he's the Omega's parent. If Dean wants another partner, someone his age by the time he's 21 - fine. Sam can live that but until then the only cock his little brother is going to have inside him is his own. 

"S-sam,..." Dean finally notices the length pushing inside him, opening him up far more than the fingers did. 

There's no friction yet, because Sam is moving slowly. But Dean doesn't mind. The feeling of his Alpha so close to him that he can't leave calms a desperate urge. Only when Sam's cock drives even deeper, Dean moans and backs down, barely aware how Sam angles his head to kiss his neck. 

"Oh," Dean says in wonder and lets his head fall against Sam's shoulder. They did this before but he hasn't grown used to it yet how having a cock inside him truly feels. 

"Just a bit more, Dean," Sam says and moves forward in slow thrusts. "Then I'm completely inside you. Can you feel it? You're clenching around me already. Like a good little omega should. Your hole is trying to tighten around me, tries to get knotted despite how big I must be for you." 

Dean goes rigid when hearing these words, just for a moment. Then he pants and rocks back, tries to fuck himself on Sam's cock though he's doing little more than helplessly writhing and twisting in Sam's arms. The thought of having Sam inside him for so long, for half an hour if it's done right with the knot pressing against flesh even more triggers something in Dean. 

"Can we do that? Please, can we do that, Sammy?" Dean whines and wishes Sam would just start to fuck him already. But all Sam does is wait, cock buried to the hilt inside Dean. 

"That has to wait," the Alpha growls and pushes the omega forwards. Fingers turn into claws while they touch Dean's neck and keep his face pressed against the pillow. "Remember, this is a lesson first an foremost. I'm taking care of you, Dean. You've to learn how get fucked. How to take a good fuck, alright?" 

Sam moves his hips a little, not hard but enough to draw a shocked moan out of Dean. Bend over like this the Alpha's dick feels ever bigger and Dean arches his back, not willing to lose a single glorious inch of it. 

"Y-yes, Sam ... Sir. I'll wait," Dean chokes as Sam's hips jerk and a single thrust makes him lie pliant under his Alpha. He wants to experience that agonizing stretch again, the thick head pressing against his prostate. "I promise ... I ... oh... oh!..." 

Raw moans fill the room, accompanied a greedy ass urging back. 

"Oh yes, you will," Sam growls. "You're going to wait for my command. The first time you get knotting happens under my explicit supervision. You don't even get to come until I give my permission. You aren't in charge anymore.Do you get this, Dean?"

He can't keep his Alpha voice in check as he starts to fuck Dean in earnest. Deep and slow at first to make Dean remember who's cock they talking about. Not that his little brother needs it. Dean is trashing in his hold, trembling and clenching because the dick inside him is so big, so good and drives so deep. 

"I said, do you get it?" Sam growls again, tightens his hold on Dean by pulling the Omega's arms back and keeping them together with one hand. 

Dean cries out, dazed by how bliss takes over when Sam fills out his ass again. He can't move, doesn't want to move because Sam's fucking him. Sam thrusts into him hard and fast, almost brutal if it weren't for Dean's delighted moans answering each time their bodies meet. 

"I-I get it," he sobs, provoked by Sam's wild hunger for him. 

The Alpha growls against his neck and this time Dean can feel the fangs, true fangs, prodding against his skin. What should be dangerous causes Dean to flex his body even more. No doubt that Sam knows what he's doing. This is a display of dominance to keep him safe. This is Sam asking of he can trust Dean to follow his orders so that he doesn't get hurt. Because it's up to Sam now to look after him. Dean is young. He doesn't know the rules or what's good for him. 

This is why Sam alters the speed of his thrusts, leaves Dean hanging on the edge on occasion just to pull him back and start the game all over again, no matter much Dean's asking, begging or pleading. 

"Good boy." Sam's praise vibrates in Dean's chest and the omega realizes that he has never felt so full before. So full of Sam. "Now Dean, let's see how long you can last. You're still young and have so much to learn. You're going to learn how to ride me, how to let me slip inside so that you never have to leave my lap in the night."

Dean lets Sam's dark voice wash over him, lets Sam take him until Dean forgets what it means to be alone. 

"Oh, yes please," Dean whimpers his approval, feverish and burning up by the pleasure crashing down on him. 

Sam's cock is still inside him, still hard and Dean doesn't want him to leave just yet. Doesn't ever want him to leave even when Sam wraps his fingers around Dean's weeping shaft. 

Finally Dean comes gasping Sam's name. He rides out his orgasm in a sharp mix of overwhelming pleasure and confusion. While he lies on the bed slightly dazed by the orgasm, all Dean can think about is how it'd feel to watch TV with having his Alpha's cock inside of him. Or to have his head in Sam's lap, sucking his brother's cock while a strong hand in his hair makes sure he stays there. Maybe this new life as Omega wouldn't be so bad, Dean thinks. He mewls and nearly comes again when Sam's cock throbs and he's filled with a hot warm melting liquid that slowly drizzles out of him when Sam draws out of him. 

Losing his brother's cock in nearly painful and Dean lets out a complaining sigh when he clenches around nothing. 

"Shh, it's alright," Sam says and drapes himself over Dean. "I know what you need but you aren't ready for that yet. Let's practice with something else first, okay?" 

With these words Sam kisses his little brother on the head and pulls out a plug from the nightstand. The toy makes a loud wet sound when Sam pushes into Dean's waiting asshole with little trouble. Yet as soon as the base is nestled against Dean's skin his little brother crawls into Sam's embrace. With a smile Sam wraps his own long legs around Dean's and tightens the bind by placing the omega's ass directly into his groin. This way his little brother can pretend that the plug inside him is his Alpha's cock and Sam is glad that Dean looks content when he goes to sleep.

**Author's Note:**

> This entire thing was written in roughly two hours. The prompt just sucked me in. I really should write more ABO.


End file.
